Dredging Works in Bunbury

Dredging Works in Bunbury

  • Bunbury
  • Community
  • Published: 2 October 2020

These works are usually undertaken twice a year, and can take up to two weeks. A trailer suction dredge removes naturally accumulated sand and silt from the shipping channel and outer harbour berths, and deposits the material at the ocean spoil ground.

The dredge is a slow moving vessel, and the usual protocols with regard to interactions with recreational craft still applys. Turbidity resulting from the dredging is usually short lived and localised. Some odour may be noticeable at times due the decaying sea grass disturbed in the shipping channel during dredging.

Last year there was some community concern regarding a sludge like material found on recreational craypots off-shore from the Binningup town beach last year. The Port commissioned Murdoch University's Marine and Fresh Water Research Laboratories (MAFRL) to investigate potential connection with the Port's routine maintenance dredging activities and the disposal of dredge spoil at the ocean spoil ground some 12.5 kilometres south of Binningup.

Water quality and sediment quality indicators were measured seasonally across seven sites stretching along 26 kilometres of coastline from the Bunbury Port in the south to the Harvey River Diversion Drain in the north to see if there were any trends occurring of consistently high phytoplankton and nutrient concentrations.

MAFRL also monitored water quality parameters during dredging works earlier this year.

The conclusion of these investigations was that concentrations of nutrients and metals were low, and petroleum hydrocarbons were not detected in the water, sediment or on the settlement plates at sites in the study area over the sampling period. It was determined that the formation of material on the settlement plates was due to natural processes, not dredging activities. 

For more information call the Bunbury Port Office on 9729 6500 or email enquiries.bunbury@southernports.com.au